Despite the improved activity of combination antiretroviral therapies in patients with HIV infection, the antiviral, immunologic, and clinical impact of such therapies appears to be incomplete and is often transient. In addition, treatment with the agents noted above may be associated with significant drug interactions and side effects. Combination therapies with complicated administration regimens also pose a challenge to some populations requiring antiretroviral therapy. Therefore, the identification of novel and conveniently administered agents in combination strategies for treating patients with HIV infection would be of great benefit. Adefovir dipivoxil, a nucleotide reverse transcriptase inhibitor, has been shown to be effective in vivo against HIV by its ability to reduce viral load measurements including p24Ag and HIV RNA. Adefovir dipivoxil at a dose of 60 mg daily has been utilized in previous trials but only as a dose reduction from 120 mg in response to clinically significant toxicities or intolerance. Previous clinical trials have demonstrated a clear dose-dependent relationship for adefovir dipivoxil related adverse events. However, no clear dose dependence has been established for the antiviral activity of adefovir dipivoxil at the doses clinically studied: 125 mg to 500 mg daily. The antiviral activity or safety profile of adefovir dipivoxil 60 mg daily has not been examined. It is possible that a daily dose of 60 mg has the same anti-HIV effect as 125 mg. Therefore, the rationale for conducting this protocol is to determine if there is antiviral activity of adefovir dipivoxil at a lower dose than those tested previously in human trials.